Bridge rectifier for diode-rectified alternating current generator

ABSTRACT

An improved bridge rectifier for an alternating current generator includes a first heat sink, an insulating layer disposed on the first heat sink, and a second heat sink disposed on the insulating layer. The second heat sink includes at least one of the following features: air passages which include external air passage slots opening an external portion of the air passages in the plateau section, or air passages which include internal air passage slots opening an internal portion of the air passages in the plateau section, or air passages which are repositioned to maximize exposure of the air passages to receive air from the alternating current generator, or air passages which include bottom channels formed in the second heat sink for receiving air from the bottom of the second heat sink, or diode receiving holes which are separated by a substantially same distance between each other for balancing thermal stress, or a second area of the second heat sink includes ridges to increase a surface area of the second area.

FIELD OF THE INVENTION

The present invention generally relates to bridge rectifiers forrectifying electrical current output from an alternating currentgenerator, and more particularly, to an improved bridge rectifier whichutilizes an improved carrier plate heat sink which more efficientlydissipates heat to properly cool the carrier plate while providingcurrent to various electrical loads such as, for example, a motor.

BACKGROUND OF THE RELATED ART

Bridge rectifiers are used to rectify current output from alternativecurrent sources, such as an alternating current generator. Bridgerectifiers for motor vehicle alternators are well known in the art andgenerally include two metal parts used as heat sinks that areelectrically insulated from each other. As a result of the current whichis transmitted therethrough, the bridge rectifier becomes heated due tothe internal power loss on each individual diode. Thus, the bridgerectifier must be properly cooled in order to handle the maximumrequired current while still being tolerant to increased temperaturesdue to internal power losses.

Each of the metal parts or carrier plates include semiconductor diodeswhich are arranged to polarize the two metal parts into respectivepositive and negative direct voltage output terminals. The diodes arethen connected to respective phase windings of an output winding of thealternating current generator.

The rectifier diodes are connected to respective carrier plates, andthese carrier plates are used as heat sinks for these diodes as well.The rectifier diodes are typically inserted by pressure in receivingbore holes of the carrier plate or heat sink, or are soldered to thecarrier plate using appropriate solder alloys. The end wires connectedto the rectifier diodes enable the rectifier diodes to be connected toexternal sources.

The heat sinks are typically constructed in the shape of a circle orcrescent and are fastened in the same plane to the alternating currentgenerator.

Various difficulties or problems have occurred using this standard dioderectifier. For example, since the diode rectifier is mounted to analternating current generator which is used with a motor, there arespace limitations within the motor, for example, which limit the size ofthe diode rectifier. One prior art solution to this problem isconstructing or fabricating the carrier plates which are connected tothe rectifier diodes into a shape which is more than a half circleapproximating the circular shape of the alternating current generator.The carrier plates are constructed as a positive heat sink and anegative heat sink and the two heat sinks are arranged coaxially inseparate planes spaced apart by an axial distance from one another. See,for example, U.S. Pat. No. 4,952,829 to Armbruster et al., incorporatedherein by reference.

Another problem which has been experienced with diode rectifiersincludes the need to carefully match the diode characteristics in orderto avoid imbalance in the amount of current conducted by the individualdiodes. If thermal imbalance is experienced, certain diodes willincrease current flow which may result in thermal runaway. Thermalrunaway involves a diode which is unable to regulate its current flowand temperature. In this situation, the diode conducts increased currentand experiences increased temperature until the individual diode is nolonger able to conduct such a high current or experience such a hightemperature, and the diode becomes destroyed. Frequently, thermalrunaway results in the destruction of an individual diode, and thedestroyed diode becomes short circuited thereby rendering the entirebridge rectifier inoperative.

Another problem which has been encountered in bridge rectifiers is thatthe bridge rectifiers must not only be able to withstand normal batterycharging current, but must also be able to supply current, perhaps asmuch as ten times the normal charging current. These increased currentsituations may occur, for example, when the motor vehicle is beingstarted. Bridge rectifiers, as discussed, are typically unable to absorbor conduct these types of excess currents and are also unable to rapidlydissipate the resulting heat. Thus, the heat generated within the bridgerectifier may destroy the individual diodes. In order for bridgerectifiers to handle these types of excessive currents and heat, itbecomes necessary to utilize a bridge rectifier which has higher currenthandling capability. Due to the space limitations of the alternatingcurrent generator, it then becomes very difficult to provide such abridge rectifier from a feasibility standpoint as well as at aneconomical cost.

A further attempt at increasing the current capacity and heatdissipating characteristics of the bridge rectifier includes themounting of semiconductor diode chips onto first and second metallicheat sinks which are electrically insulated from each other by a thinsheet of electrical insulating material. The diode chips are thencovered by a protective insulating coating after connection to therespective heat sink. One of the metallic heat sinks includes a finnedarea which is subjected to cooling air when the bridge rectifier ismounted to the generator. The heat sink with the plurality of finsincludes twelve air passages. This type of bridge rectifier is shown inU.S. Pat. No. 4,606,000 to Steele et al., incorporated herein byreference.

FIGS. 1a-1b are illustrations of a similar bridge rectifier as depictedin Steele et al. In FIG. 1a, combined alternator cover and carrier plate2 includes carrier plate or heat sink 4 connected to alternator cover 6(only partially depicted to expose underlying plate 4). Carrier plate 4includes receiving bore holes 8 which are formed for receiving thediodes. Carrier plate 4 includes alternator mounting holes 10 formounting carrier plate 4 to the alternator cover 6 via standardconnection means such as a bolt or screw connection. Alternator cover 6includes three main alternator air passages which interact with thetwelve air passages 14 in corner plate 4, thereby cooling radiating fins13. As depicted in FIG. 1b (alternator cover 6 omitted for simplicity),carrier plate 4 is of a rectangular shape (in side view) having the airpassages 14 completely disposed within carrier plate 4.

FIG. 2 is an illustration of the positioning of the bridge rectifier 1within a standard alternating current generator generally designatedwith reference letter G. As depicted in FIG. 2, the completely assembledbridge rectifier 1 which includes carrier plate 4 and cover 1a isconnected to alternator cover 6 via any standard connection means, suchas screws 7. Reference numeral 3 denotes the bottom of carrier plate 4,while reference numeral 5 denotes the top of carrier plate 4. Bridgerectifier 1 is also connected to regulator 9. As mentioned previously,the standard bridge rectifier shown in Steele et al. and FIGS. 1a-1b arewell known in the art and may also be purchased from WetherillAssociates, Inc. of Royersford, Pa. as part no. 31-113 including coverpart no. 46-1858.

While there have been, as described above, several attempts to increasethe current and heat capacity of the bridge rectifier, none of theseprior attempts have been completely satisfactory. That is, none of theseprior art attempts have increased the current and heat capacity of thebridge rectifier in an economical manner.

As a result of our dissatisfaction with existing bridge rectifiers, wehave discovered a significant problem which is the basis of the poorperformance characteristics of prior art bridge rectifiers. This problemresides in the poor performance characteristics of the carrier plate,and the resulting defects or failures which arise therefrom. Inaddition, we have also recognized that while the surface area of thecarrier plate is restricted by the circular shape of the alternatingcurrent generator, the depth of the carrier plate is not. Also, we havediscovered new configurations of the carrier plate which more evenlydistribute the electric current and resulting heat and more efficientlycool the carrier plate by facilitating increased passage or flow of airthrough the carrier plate.

SUMMARY OF THE INVENTION

It is therefore, a feature and benefit of the present invention toprovide an improved bridge rectifier which is able to increase thecurrent and heat capacity characteristics of the bridge rectifier at aneconomical cost.

It is another feature and advantage of the present invention to providean increased current and heat capacity bridge rectifier which includes areduced number of air passages and radiating fins in the carrier plate.The air passages have been widened and the radiating fins have also beenincreased in width in order to permit additional air to flow into thecarrier plate while maintaining a strong structural base in the carrierplate to provide the necessary heat dissipation and current handlingcapabilities.

It is another feature and advantage of the present invention to providefor the carrier plate increased height thereby increasing the amount ofmetal in the carrier plate to increase the current and thermalcharacteristics. We have discovered that while it is difficult toincrease the surface area of the carrier plate in the radial direction,i.e., in the same plane as the carrier plate, it is neverthelesspossible to increase the depth or height of the radiating fin section inthe carrier plate to be coextensive with the cover of the carrier platesince this additional space had not been previously utilized.

It is another feature and advantage of the present invention toreposition the air passages in the carrier plate with respect to thealternator cover passages in order to optimize or increase the amount ofair which may flow from the alternator through the air passages in thecarrier plate. This additional air which flows through the passages andthrough the carrier plate thereby permits enhanced cooling of thecarrier plate. The carrier plate is then able to dissipate additionalheat due to higher currents.

As another feature and advantage of the present invention, the presentinvention provides air passages in the carrier plate which include slotswhich are exposed to the outside for entraining additional air in thecarrier plate.

It is another feature and advantage of the present invention to providebottom channels in the carrier plate which extend from the inner radiusof the carrier plate to the air passage on the bottom of the carrierplate for permitting air to pass beneath the diodes, enhancing thecooling of the diodes. These bottom channels may also be filleted orrounded up for better air admission or intake.

Another feature and advantage of the present invention is therepositioning of the diode receiving bore holes in the carrier plate toequalize the distances between each of the diodes when mounted in thecarrier plate. This positioning of the diodes equalizes or creates moreuniform heat dissipation throughout the carrier plate. By positioningthe diodes in a symmetrical fashion in the carrier plate, the thermalstress is reduced by equalizing the amount of HGAT which is conducted bythe carrier plate.

Another feature and advantage of the present invention is the specificconfiguration of the air passages within the carrier plate. Inparticular, the inner walls of the air passages have been filleted orangled from the bottom of the carrier plate to the top of the carrierplate to increase the speed of the air which enters the bottom channelsin the carrier plate. This increase in air speed provides a faster flowof air through the carrier plate, thereby providing better coolingcharacteristics.

Another feature and advantage of the present invention is the providingof ridges on the surface area of the carrier plate which create an airwrap from the bottom to the top of the carrier plate. These ridgesprovide channels for drawing the air directly into the air passages fromthe surface of the carrier plates, and thereby, provide enhanced coolingof the carrier plate.

Another feature and advantage of the present invention is to fillet orround the various edges of the carrier plate for improving the air flowover the diode area in the carrier plate. The edges are rounded withoutsignificantly reducing the amount of metal in the carrier plate whichmight reduce the carrier plate's capacity to conduct electricity anddissipate heat.

The present invention advantageously includes identification andconsideration of the following factors:

Rectifying Factors:

Most alternators are 3-phase type. The `rotor` field rotation (whenrunning DC current through it) generates AC current on the 3 fixedisolated windings of the `stator` field, called phases. There are twotypical connections of the 3 phases, i.e., in a triangle and in a star.In both types, each phase is connected on one of its edges to a pair ofdiodes: to one diode on its anode and to the other diode on its cathode.The positive cycle of the AC current goes to the anode, and the negativeto the cathode. This is rectifying AC to DC. Since there are 3 pairs ofdiodes, all 3 free cathodes are connected to the (+)BAT, and the freeanodes to the (-)BAT, and the DC circle is closed.

Heat:

The electrical current through a diode creates heat. The heat affectsnegatively the current capability of a diode. Thus, temperature/currentcapability are in opposite relation. Over a given temperature a diode isdestroyed. Therefore on an alternator which generates high current, itis most necessary to cool the diodes by heat sinks and improve the heatdissipation of the heat sinks by increasing the mass and flowing airover/through them.

The present invention satisfies the above features and benefits byproviding an improved bridge rectifier for an alternating currentgenerator including a first heat sink having a first set of diodes, andan insulating layer disposed on the first heat sink. In addition, theimproved bridge rectifier includes a second heat sink disposed on theinsulating layer. The second heat sink includes a base section includingfirst and second areas, a second set of diodes, and diode receivingholes in the base section and receiving the second set of diodestherein. The second heat sink also includes a plateau section disposedon the first area of the base section, and air passages disposed in andextending through the base and plateau sections. The improved bridgerectifier further includes connectors, connecting the first heat sinkand the second heat sink together with the insulating layer disposedtherebetween, a cover connected to the base section and covering thesecond area of the base section, and a capacitor connected to the coverand to the second heat sink.

The second heat sink includes at least one of the following: airpassages which include external air passage slots opening an externalportion of the air passages in the plateau section for enhanced coolingof the second heat sink, or air passages which include internal airpassage slots opening an internal portion of the air passages in theplateau section for enhanced cooling of the second heat sink, or airpassages which are repositioned to maximize exposure of the air passagesto receive air from the alternating current generator, or air passageswhich include bottom channels formed in the second heat sink forreceiving air from the bottom of the second heat sink for enhancedcooling of the second heat sink, or diode receiving holes which areseparated by a substantially same distance between each other forbalancing thermal stress resulting in uniform heat conduction by thesecond heat sink, or a second area of the second heat sink includesridges to increase a surface area of the second area for enhancedcooling of the second heat sink.

In another embodiment, a method of increasing current transferred from acurrent generating source includes the steps of electrically connectinga carrier plate having a base section to the current generating source,and adding a plateau section on the base section providing additionalmass to the carrier plate to improve conductive and heat capacitycharacteristics of the carrier plate. The method further includesproviding air passages disposed in and extending through the base andplateau sections which provide air for cooling the carrier plate.

The method further includes at least one step of providing external airpassage slots in the air passages to open an external portion of the airpassages in the plateau section providing enhanced cooling of thecarrier plate, or providing internal air passage slots in the airpassages to open an internal portion of the air passages in the plateausection providing enhanced cooling of the carrier plate, orrepositioning the air passages to maximize exposure of the air passagesto receive air from the current generating source, or providing bottomchannels in the air passages of the carrier plate to receive air fromthe bottom of the carrier plate providing enhanced cooling of thecarrier plate, or providing diode receiving holes separated by asubstantially same distance between each other to balance thermal stressresulting in uniform heat conduction by the carrier plate, or providingridges on the second area of the carrier plate to increase a surfacearea of the second area providing enhanced cooling of the carrier plate.

These, together with other objects and advantages which will besubsequently apparent, reside in the details of construction andoperation as more fully hereinafter described and claimed, withreference being had to the accompanying drawings forming a part hereof,wherein like numerals refer to like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a-1b are respective bottom and side views of a bridge rectifieraccording to the prior art;

FIG. 2 is an exploded view showing the general connection of the bridgerectifier according to the prior art;

FIGS. 3a-3c are respective side, top and section views of the bridgerectifier according to the first embodiment of the present invention;

FIGS. 4a-4c are respective side, top and section views of the bridgerectifier of the present invention including cut out passages;

FIGS. 5a-5c are respective side, top and section views of the bridgerectifier of the present invention including air passage slots;

FIG. 6 is a bottom view of the bridge rectifier of the present inventionwherein the air passages have been repositioned;

FIG. 7 is a bottom view of the bridge rectifier including bottomchannels;

FIGS. 8a-8b are respective section and side views of the bridgerectifier including bottom channels shown in FIG. 7;

FIG. 9 is a bottom view of the bridge rectifier of the present inventionillustrating the repositioning of the diode bore hole;

FIGS. 10a-10d are respective bottom, section, enlarged and section viewsof the bridge rectifier of the present invention including radiatingfins and air passages with tilting or angled walls;

FIGS. 11a-11c are respective top and enlarged views of the bridgerectifier of the present invention including ridges on the upper surfaceof the carrier plate;

FIGS. 12a-12b are respective section and top views of the bridgerectifier of the present invention including fillets along the edges ofthe carrier plate;

FIGS. 13a-13f are combined views of the various features of the presentinvention illustrated together;

FIGS. 14a-14b are respective top and side views of the bridge rectifierof the present invention as mounted to the alternator front cover;

FIGS. 15a-15b are respective side and bottom views of the bridgerectifier of the present invention as mounted to the front cover of thealternator;

FIGS. 16a-16c are respective exploded, top, and side views of the bridgerectifier of the present invention;

FIGS. 17a-17f are views of the bridge rectifier of the present inventionillustrating the important dimensional characteristics; and

FIG. 18 is a table illustrating the approximate dimensions of theimportant dimensional characteristics of FIGS. 17a-17f.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

We have discovered that many of the failures which have occurred in theprior art bridge rectifier devices are a result from the failure of thecarrier plate in the bridge rectifier to handle excessive current andtemperature. We have also discovered that the basic problem which hadnot been addressed by the prior art is how to make the carrier plate orheat sink itself capable of absorbing or bearing these excessiveconditions while still being able to manufacture the bridge rectifier atan economical cost. We have further recognized the problem of spacelimitations within the alternating current generator, and in particular,the specific configuration of the alternating current generator whichimposes various different forms of space limitations on the bridgerectifier when mounted and disposed within the alternating currentgenerator. We discovered that increasing the height of the carrier platewill not implicate these space limitations. Finally, we have recognizedthe prior art's inability to properly cool the bridge rectifier, sincethe prior art bridge rectifier was not configured or structured tofacilitate the introduction of air to cool the carrier plate and diodes.

Having identified each of the above problems after considerable andcareful study, we have solved these problems by providing a bridgerectifier in accordance with the principals of the present invention asdiscussed below.

FIGS. 3a-3c are various views of the bridge rectifier according to thepresent invention. In FIG. 3a, carrier plate 4a is illustrated from itsside. As shown in FIG. 3a, carrier plate 4a includes the base section 16with an additional heat conducting plateau section 18. Air passages 14are arranged to pass through or be disposed within both base section 16and plateau section 18. The present invention includes this additionalheat conducting plateau section 18 because we recognized that while thealternating current generator limits the surface area of the carrierplate, there is additional space which may be utilized within thealternating current generator to increase the height of the carrierplate by providing plateau section 18. Thus, carrier plate 4a includesadditional mass or structure which may be utilized to absorb additionalincreased current and heat conditions.

As shown in FIGS. 3a-3b, carrier plate 4a also includes surface junction22 which provides an angle shape of carrier plate 4a for dispositionwithin the alternating current generator as well as notch 20 which mayalso be used for the positioning of carrier plate 4a. Finally, as shownin FIG. 3b, carrier plate 4a includes diode bore holes 8 which are usedto receive the diodes and for mounting the diodes to carrier plate 4a.

FIG. 3c is a sectional view of carrier plate 4a in accordance withsection lines 3c--3c shown in FIG. 3b. As shown in FIG. 3c, air passage14 extends through base section 16 and plateau section 18. Plateau wall11 and external wall 28 are preferably integral with base section 16.However, plateau wall 11 and external wall 28 may be formed of aseparate structure using a similar material as base section 16 andjoined to base section 16 in accordance with standard techniques in theart. Air enters and exits base section 16 as indicated by arrow 21.

As shown in FIGS. 3a-3c, carrier plate 4a includes nine (9) air passages14 which is also considered to be a significant advance over the priorart carrier plate which included twelve (12) air passages. Inparticular, we have discovered that by providing fewer but larger airpassages with thicker or more substantial radiating fins, better currentabsorption and heat tolerance characteristics are experienced by thecarrier plate. In particular, it was discovered that by increasing thewidth of the air passages additional mass was added to carrier plate 4aresulting in increased heat tolerance. In addition, we also discoveredthat by increasing the size of the air passages, the carrier plate wasmore efficiently cooled.

FIGS. 4a-4b are respective side and top views of carrier plate 4b of thepresent invention including cutout air passages 14a. As a result of airpassages 14a, alternating air passage slots 11a and plateau components24 are formed in the modified plateau section 18a. Air passage slots 11aprovide additional ventilation and more even distribution of the airwhich is entrained from the alternating current generator throughoutcarrier plate 4b for more efficient cooling of the base section 16 andadditional heat conducting plateau section 18a as well as the diodeswhich are inserted in diode bore holes 8.

FIG. 4c is a cross section of cut-out air passages 14a as shown by thesectional lines 4c--4c in FIG. 4b. As shown in FIG. 4c, cut-out airpassage 14a extends through plateau section 18a and base section 16. Inaddition, cut-out air passage 14a includes air passage slot 11a forincreased ventilation of carrier plate 4b and the diodes which arepositioned therein. Air enters and exits base section 16 as indicated byarrow 23a, and additional air enters and exits plateau section 18a asindicated by arrow 23b. As indicated previously, the present inventionrecognizes that failures in the bridge rectifier were resulting, inpart, due to the carrier plate's inability to be properly cooled, aswell as the carrier plate's inability to properly cool the diodes whichwere imbedded therein. Thus, cut-out air passages 14a provide additionalventilation in cooling of carrier plate 4b and the diodes.

FIGS. 5a-5b illustrate respective side and top views of carrier plate 4cincluding internal air passage slots 28a. As shown in FIGS. 5a and 5b,carrier plate 4c includes base section 16 and plateau section 18b.Additional heat conducting plateau section 18b includes air passage slot11a as well as internal air passage slot 28a. Additional internal airpassage slot 28a provides additional cooling by permitting air to morereadily flow through plateau components 24 of plateau section 18b intoair passages 14b.

FIG. 5c is a sectional view of section 5c--5c designated in FIG. 5b. Asshown in FIG. 5c, air passages 14b include air passage slot 11a as wellas internal air passage slot 28a. As explained above, this additionalinternal air passage slot 28a provides enhanced cooling and ventilationthroughout carrier plate 4c thereby providing a bridge rectifier withenhanced current dissipation and temperature tolerance. Air enters andexits base section 16 as indicated by arrow 25a, and additional airenters and exits plateau section 18b as indicated by arrows 25b.

FIG. 6 is a bottom view of the bridge rectifier of the presentinvention, wherein the air passages have been repositioned to facilitateair flowing from the alternating current generator to bridge rectifier 2via alternating cover 6. As shown in FIG. 6, air passages 14 in carrierplate 4d have been repositioned to minimize the amount of overlapbetween air passages 14 and alternator cover 6 by maximizing the numberof air passages which are exposed to main alternating air passages 12 ofalternator cover 6. As also shown in FIG. 6, nine air passages areillustrated where only half of air passage 17 is covered by alternatorcover 6 and all of air passage 15 is exposed through main alternator airpassage 12. Thus, only a total of half of one air passage is unable tobe used for receiving air from the alternating current generator forcooling carrier plate 4d of bridge rectifier 2. In contrast, FIG. 1a ofthe prior art shows that at least two air passages 14 are covered byalternator cover 6, thereby reducing the amount of air which isintroduced to carrier plate 4, resulting in inefficient cooling ofcarrier plate 4.

FIG. 7 is a bottom view of the carrier plate in accordance with thepresent invention which includes bottom channels. As shown in FIG. 7,carrier plate 4e includes bottom channels 30 which extend underneath airpassages 14c for enhanced cooling of carrier plate 4e.

FIGS. 8a-8b are respective section and side views of carrier plate 4e.In particular, FIG. 8a is a sectional view of section 8a--8a which isillustrated in FIG. 7. As shown in FIG. 8a, air passage 14c includesbottom channel 30 which permits air to enter air passage 14c as shown byreference numerals 42 and 44. External wall 28 has been rounded at thebottom near bottom channels 30 to facilitate air introduction in airpassage 14c. Base section 16a is also preferably rounded at corners 36and 38 to further facilitate air introduction in bottom channel 30. Notethat the rounding at corners 34, 36 and 38 are preferably minor innature to prevent any significant amount of mass or material beingremoved from carrier plate 4e thereby preventing any significantreduction in current dissipation and temperature characteristics of thebridge rectifier.

FIG. 8b also shows that bottom channel 30 is rounded at corners 31 and33 to further facilitate air introduction and cooling of carrier plate4e.

FIG. 9 is a bottom view of carrier plate 4f of the present inventionwhich illustrates the repositioning of the diode bore holes forequalized current dissipation of the carrier plate. In FIG. 9, carrierplate 4f has the center diode bore hole 8 transferred or repositioned todiode bore hole 8a as illustrated. This repositioning of diode bore hole8a results in distances 8b and 8c being substantially similar to eachother. Thus, all three of the diode bore holes are separated byapproximately the same distance from one another to further facilitatemore uniform heat dissipation of carrier plate 4f.

FIG. 10a is a bottom view of the carrier plate of the present inventionwhich includes radiating fins and air passages with tilting or angledwalls. As shown in FIG. 10a, carrier plate 4g includes air passages 14dto have tilting or angled walls. FIG. 10c is an enlarged view of thetilting or angled walls of air passages 14d. As shown in FIG. 10c, airpassages 14d are angled to have a greater opening at the bottom ofcarrier plate 4g and to have a smaller opening at the top of carrierpage 4g. This angling of air passages 14d permits additional air toenter air passage 14d and be accelerated through the air passage foradditional or enhanced cooling of carrier plate 4g.

FIG. 10b is a sectional view of air passage 14d in accordance withsection 10b--10b as shown in FIG. 10a. As shown in FIG. 10b, air passage14d preferably includes bottom channel 30 for permitting air designatedby reference numerals 42 and 44 to enter from the bottom of carrierplate 4g. Bottom channel 30 is also preferably rounded at areas 36 and38 as described previously. Base section 16b and external wall 28b areconstructed so as to lean or tilt from the bottom to the top of carrierplate 4g as illustrated between points 38 and 48 of section 16b andbetween points 50 and 52 of external wall 28b. This tilting of basesection 16b and external wall 28b creates acute angles beta β and alphaα, respectively which provide the angle of the tilting of air passage14d.

FIG. 10d is another sectional view of air passage 14d which alsoincludes the additional tilting of base section 16c at area 49 andexternal wall 28c at area 51 which results in angles theta θ and phi φrespectively. This additional tilting of base section 16c and externalwall 28c on the external portions of the carrier plate, also facilitateadditional or increased heat dissipation and temperature characteristicsof the carrier plate without substantially removing a significant amountof mass from the carrier plate which would hinder current dissipationand heat absorption characteristics.

FIGS. 11a-11c are top and enlarged views of the carrier plate 4h of thepresent invention including ridges on the upper surface of the carrierplate. As shown in FIG. 11a, carrier plate 4h includes ridges 54 whichhave been enlarged in FIGS. 11b and 11c. As shown in FIGS. 11b-11c,ridges 54 include peaks 56 and 60 and low point 58 creating spacing 62between ridges and depth 64 of the ridges. In addition, each ridge 54 isconfigured in accordance with a predetermined angle such as lambda λ asshown in FIG. 11c. This ridging of the upper surface of carrier plate 4hcreates additional surface area for absorbing and dissipating currentand temperature to enhance the operability of carrier plate 4h. Further,these ridges also facilitate the introduction of air to the air passagesby providing a more focused passageway which creates an air wrap overthe surface of carrier plate 4h. Thus, carrier plate 4h experiencesenhanced cooling and current dissipation characteristics which have beenunable to have been achieved by the prior art.

FIGS. 12a-12b are respective top and section views of the carrier plateof the present invention including fillets along the edges of thecarrier plate. As shown in FIG. 12a, carrier plate 4i includes ridges 54with fillets 66 along the outer edges of the carrier plate. FIG. 12b isa section view as illustrated by section lines G--G in FIG. 12a. Asshown in FIG. 12b, diode bore hole 8 is positioned amidst ridges 54 withfillet 66. Also shown is the positioning of bottom channel 30 withrounded edges 36 and 38 within carrier plate 4i. Thus, these additionalfillets 66 facilitate the flow of air from the external of carrier plate4i toward the air passages which allows additional air to flow over thediodes positioned in diode bore holes 8 and provide additional coolingto the carrier plate 4i as well as, in particular, the diodes implantedin carrier plate 4i.

FIGS. 13a-13f are views of the various features of the carrier plate ofthe present invention all viewed together. Since these various viewshave been discussed in detail in connection with FIGS. 3a-12b,additional discussion of these figures is not necessary.

FIGS. 14a-14b are respective top and side views of the bridge rectifierof the present invention as mounted in the alternating currentgenerator. As shown in FIG. 14a, alternating current generator 70includes the bridge rectifier mounted therein where air passages 14 ofthe bridge rectifier are exposed via the windows 12 of alternator frontcover 6 in accordance with the principals of the present invention. Inaddition, terminal 72 of the bridge rectifier are exposed for connectionto an external source for receiving and limiting the current. FIG. 14bshows similar details from a side view of the alternating currentgenerator.

FIGS. 15a-15b are side and bottom views of the bridge rectifier of thepresent invention as mounted in the alternating current generator. Asshown in FIG. 15b, bridge rectifier 1 is mounted within the alternatingcurrent generator 70 including rectifier cover 1a. FIG. 15b alsoillustrates the placement of regulator 9 and brushes 76 with respect tobridge rectifier 1 of the present invention. Alternator front cover 6 isalso illustrated in FIGS. 15a-15b as mounted to bridge rectifier 1 viamounting screws 7. Terminals 72 are also illustrated in FIG. 15a whichpermit bridge rectifier 1 to be connected to external sources such asthe alternator front cover.

FIG. 16a is an exploded view of the entire construction of the bridgerectifier of the present invention. As shown in FIG. 16a, carrier plates4a-4i represent the various configurations of the carrier plate inaccordance with the principals of the present invention discussedpreviously. In addition, diodes 78 are disposed in any of carrier plates4a-4i as previously discussed in the diode bore holes. Carrier plate4a-4i is preferably made from aluminum and polarized with a positivecharge. In addition, the three diodes 78 which are disposed in the diodebore holes conduct cathode to case. Copper heat sink 84 includes copperheat sink diodes 82 which are soldered to its top surface. Copper heatsink 84 is polarized with a negative charge and the three diodes 82conduct from anode to case. Insulator 80 is disposed between carrierplate 4a-4i and copper heat sink 84 and is spread with a silicon greaseto provide electrical insulation but thermal conductivity betweencarrier plate 4a-4i and copper heat sink 84. Plastic cover 1a includescopper terminal 72 and receives each of the diodes 78 and 82 forconnecting all six diodes to an external source. Terminals 72 are thenconnected to the alternator, three of which are connected to the statorphases and one of the terminals is connected to the regulator. Capacitor79 is electrically connected between carrier plate 4a-4i and copper heatsink 84. Plastic rivets 86 are used to connect carrier plate 4a-4i andcopper heat sink 84 together and mounting screws 7 mounts the entirestructure to the alternator front cover. FIG. 16b shows the structure ofthe entire bridge rectifier as assembled in correspondence with theexploded view of FIG. 16a, and FIG. 16c shows a side view of theassembled bridge rectifier.

FIGS. 17a-17f are various views of the carrier plate of the presentinvention illustrating the important dimensional characteristics of thecarrier plate. Further, FIG. 18 is a table which provides theapproximate dimensions of the important dimensional characteristics asillustrated in FIGS. 17a-17f.

In accordance with the above principals of the present invention, animproved bridge rectifier is provided which is able to limit and absorbhigher currents and tolerate increased temperature characteristics byproviding an improved carrier plate which is able to be more efficientlycooled and able to tolerate increased current and temperatureconditions.

The many features and advantages of the present invention are apparentfrom the detailed specification, and thus, it is intended by theappended claims to cover all such features and advantages of theinvention which fall within the spirit and scope of the invention.Further, since numerous modifications and variations will readily occurto those skilled in the art, it is not desired to limit the invention tothe exact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto falling within the scope of the invention.

We claim:
 1. A bridge rectifier for an alternating current generator,comprising:a first heat sink having a first diode; an insulating layerdisposed on said first heat sink; a second heat sink disposed on saidinsulating layer, said second heat sink includinga base sectionincluding first and second areas; a second diode; diode receiving holesin said base section and receiving said second diode therein; a plateausection disposed on the first area of said base section; and airpassages disposed in and extending through said base and plateausections; connectors, connecting said first heat sink and said secondheat sink together with said insulating layer disposed therebetween; acover connected to said base section and covering the second area ofsaid base section; and a capacitor connected to said cover and to saidsecond heat sink, wherein said second heat sink includes at least oneof:said air passages include external air passage slots opening anexternal portion of said air passages in said plateau section forenhanced cooling of said second heat sink; said air passages includeinternal air passage slots opening an internal portion of said airpassages in said plateau section for enhanced cooling of said secondheat sink; said air passages are repositioned to maximize exposure ofsaid air passages to receive air from the alternating current generator;said air passages include bottom channels formed in said second heatsink for receiving air from the bottom of said second heat sink forenhanced cooling of said second heat sink; said diode receiving holesare separated by a substantially same distance between each other forbalancing thermal stress resulting in uniform heat conduction by saidsecond heat sink; and said second area of said second heat sink includesridges to increase a surface area of said second area for enhancedcooling of said second heat sink.
 2. A bridge rectifier as recited inclaim 1, wherein said plateau section adds additional mass to saidsecond heat sink to improve conductive and heat capacity characteristicsof said second heat sink and of the bridge rectifier.
 3. A bridgerectifier as recited in claim 1, wherein said plateau section extendsabove said base section and is substantially even with said cover.
 4. Abridge rectifier as recited in claim 1, wherein said plateau and basesections are integral.
 5. A bridge rectifier as recited in claim 1,wherein:the alternating current generator includes a front cover, thebridge rectifier is connected to the front cover forming a connectionzone therebetween, the connection zone includes a cavity, and saidplateau section extends above said base section and within the cavity ofthe connection zone.
 6. A bridge rectifier as recited in claim 1,wherein said air passages comprise nine air passages for enhancedcooling and increased temperature tolerance of said second heat sink. 7.A bridge rectifier as recited in claim 1, wherein said second heat sinkis filleted at an outer edge of the second area for improving air flowover the second area for enhanced cooling of the second diode.
 8. Abridge rectifier as recited in claim 1, wherein said air passages aretapered inwardly from said base section to said plateau section forspeeding up air flow through said air passages and for enhanced coolingand increased temperature tolerance of said second heat sink.
 9. Abridge rectifier as recited in claim 1, wherein said internal andexternal air passage slots create a suction operation for sucking airover the second area and said second diode of said base section forenhanced cooling and increased temperature tolerance of said seconddiode and said second heat sink.
 10. A bridge rectifier as recited inclaim 1, wherein the bottom channels are filleted for facilitatingintroduction of air through the bottom channels for enhanced cooling andincreased temperature tolerance of said second heat sink.
 11. A carrierplate of a bridge rectifier for use in an alternating current generator,comprising:a base section including first and second areas; a plateausection disposed on the first area of said base section, said plateausection adding additional mass to the carrier plate to improveconductive and heat capacity characteristics of the carrier plate and ofthe bridge rectifier and extending above said base section; and airpassages disposed in and extending through said base and plateausections, wherein the carrier plate further includes at least oneof:said air passages include external air passage slots opening anexternal portion of said air passages in said plateau section forenhanced cooling of the carrier plate; said air passages includeinternal air passage slots opening an internal portion of said airpassages in said plateau section for enhanced cooling of the carrierplate; said air passages are repositioned to maximize exposure of saidair passages to receive air from the alternating current generator; saidair passages include bottom channels formed in the carrier plate forreceiving air from the bottom of the carrier plate for enhanced coolingof the carrier plate; diode receiving holes separated by a substantiallysame distance between each other for balancing thermal stress resultingin uniform heat conduction by the carrier plate; and said second area ofthe carrier plate includes ridges to increase a surface area of saidsecond area for enhanced cooling of the carrier plate.
 12. A carrierplate as recited in claim 11, wherein said plateau and base sections areintegral.
 13. A carrier plate as recited in claim 11, wherein said airpassages comprise nine air passages for enhanced cooling and increasedtemperature tolerance of the carrier plate.
 14. A carrier plate asrecited in claim 11, wherein the carrier plate is filleted at an outeredge of the second area for improving air flow over the second area forenhanced cooling of the surface of the carrier plate.
 15. A carrierplate as recited in claim 11, wherein said air passages are taperedinwardly from said base section to said plateau section for speeding upair flow through said air passages and for enhanced cooling andincreased temperature tolerance of said carrier plate.
 16. A bridgerectifier as recited in claim 11, wherein said internal and external airpassage slots create a suction operation for sucking air over the secondarea and diodes embedded in said base section for enhanced cooling andincreased temperature tolerance of the diodes and the carrier plate. 17.A bridge rectifier as recited in claim 11, wherein the bottom channelsare filleted for facilitating introduction of air through the bottomchannels for enhanced cooling and increased temperature tolerance of thecarrier plate.
 18. A carrier plate of a bridge rectifier for use in analternating current generator, comprising:base section means includingfirst and second areas, for connecting the carrier plate to an externalsource; plateau section means disposed on and extending above the firstarea of said base section means, for adding additional mass to thecarrier plate to improve conductive and heat capacity characteristics ofthe carrier plate; and air passage means disposed in and extendingthrough said base and plateau sections, for providing air through thecarrier plate for cooling the carrier plate, wherein the carrier platefurther includes at least one of:said air passage means includesexternal air passage slot means for opening an external portion of saidair passages in said plateau section and for enhanced cooling of thecarrier plate; said air passage means include internal air passage slotmeans for opening an internal portion of said air passages in saidplateau section and for enhanced cooling of the carrier plate; said airpassage means are repositioned to maximize exposure of said air passagesto receive air from the alternating current generator; said air passagemeans include bottom channel means formed in the carrier plate forreceiving air from the bottom of the carrier plate and for enhancedcooling of the carrier plate; diode receiving means separated by asubstantially same distance between each other for balancing thermalstress resulting in uniform heat conduction by the carrier plate; thesecond area of the carrier plate includes ridge means for increasing asurface area of said second area and for enhanced cooling of the carrierplate.
 19. A method of increasing current transferred from a currentgenerating source, comprising the steps of:electrically connecting acarrier plate having a base section to the current generating source;adding a plateau section on the base section providing additional massto the carrier plate to improve conductive and heat capacitycharacteristics of the carrier plate; andproviding air passages disposedin and extending through the base and plateau sections providing air forcooling the carrier plate, and wherein the method further includes atleast one step of:providing external air passage slots in the airpassages to open an external portion of the air passages in the plateausection providing enhanced cooling of the carrier plate; providinginternal air passage slots in the air passages to open an internalportion of the air passages in the plateau section providing enhancedcooling of the carrier plate; repositioning the air passages to maximizeexposure of the air passages to receive air from the current generatingsource; providing bottom channels in the air passages of the carrierplate to receive air from the bottom of the carrier plate providingenhanced cooling of the carrier plate; providing diode receiving holesseparated by a substantially same distance between each other to balancethermal stress resulting in uniform heat conduction by the carrierplate; providing ridges on the second area of the carrier plate toincrease a surface area of the second area providing enhanced cooling ofthe carrier plate.
 20. A method of increasing current transferred from acurrent generating source, comprising the steps of:electricallyconnecting a carrier plate having a base section to the currentgenerating source; and providing air passages disposed in and extendingthrough the base section providing air for cooling the carrier plate,and wherein the method further includes at least one step of:providingexternal air passage slots in the air passages to open an externalportion of the air passages in the base section to cool the carrierplate; providing internal air passage slots in the air passages to openan internal portion of the air passages in the base section to cool thecarrier plate; repositioning the air passages to maximize exposure ofthe air passages to receive air from the current generating source;providing bottom channels in the air passages of the carrier plate toreceive air from the bottom of the carrier plate to cool the carrierplate; providing diode receiving holes separated by a substantially samedistance between each other to balance thermal stress resulting insubstantially uniform heat conduction by the carrier plate; providingridges on the second area of the carrier plate to increase a surfacearea of the second area to cool the carrier plate.